While wind sheltered features should offer great riding, be very cautious if you poke out into wind exposed terrain. Fresh sensitive wind slabs are expected to continue to form as winds pick up over the next few days.
Confidence
Moderate - Wind speed and direction is uncertain on Wednesday
Weather Forecast
Light snowfall, cool temperatures and moderate westerly winds are expected for the first half of the workweek. There is potential for a significant warm up on Thursday. Stay tuned for details.MONDAY: Broken cloud cover, freezing level at valley bottom, light to moderate southwest wind, isolated snow flurries, 1 to 5 cm possible. TUESDAY: Broken cloud cover, freezing level at valley bottom, light to moderate west wind, 2 to 10 cm of snow possible.WEDNESDAY: Scattered cloud cover, freezing level at valley bottom, strong to extreme west/northwest wind, isolated snow flurries, 1 to 5 cm possible.Visit avalanche.ca/weather for a more detailed mountain weather forecast.
Avalanche Summary
On Saturday, two small size 1 wind slabs were triggered by skiers. Some loose dry avalanches to size 1.5 were observed on Friday in the Elk Valley North, near Crown Mountain. The deep persistent slab problem is a low probability/high consequence scenario that warrants extra caution around large open slopes, especially in shallow snowpack areas. There was a report on Tuesday of a size 3.5 avalanche at Mt Hosmer in the Lizard/Flathead region that released on or stepped down to the deep weak layer near the ground. On Wednesday we had a report from the Lizard range of another size 3.0 deep persistent avalanche on a northeast aspect in the alpine. Avalanche activity on Wednesday near Elkford was limited to loose snow up to size 1.5.
Snowpack Summary
On Saturday night the region picked up 2 to 20 cm, with the Castle area being the clear winner. This storm snow rests upon last weeks ageing storm slab. The mid-pack in this region is well settled, but the bottom third of the snowpack is composed of weak facets. Recent snow profile tests have produced failures with moderate input that released suddenly down 75 cm on the facetted crystals. In the Crowsnest North late last week up to 35 cm of recent storm snow lies above various old surfaces. Near Elkford up to 20 cm of old storm snow sits above a melt/freeze crust. Approximately 100-120 cm of settled snow sits above the weak layer of sugary facets that developed during the cold spell in December. Snow profile tests indicate hard shears in this location where the facets are sitting on a hard wind crust.
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.